DORAL, Fla. (AP) - Ernie Els has been playing at Doral for two decades, so the approaching roar of jet engines over the Blue Monster late in the afternoon is not unusual. What got his attention was the sound of chopping rotors.

The Donald had returned.

The helicopter belonging to Donald Trump, the proud owner of what is now Trump National Doral, was making another landing. A two-club wind became a four-club wind. It was quite a scene, and the Big Easy smiled big as he said, “I think that thing has come and gone seven times today.”

Els then asked the more pertinent question of the day.

“What are the boys saying about this place?” he said Wednesday as he finished up a twilight practice round on a course that is entirely different under the handiwork of Gil Hanse.

The answer: Check back on Thursday.

Because that’s when it counts.

The Cadillac Championship gets underway with great uncertainty - about the golf course, about Tiger Woods, about who is No. 1.

Even the players who have been here almost as long as 20-year-old Jordan Spieth has been on earth are starting from scratch this week. The routing of the 18 holes goes in the same direction. Everything else about the place is new.

Everything.

Consider a release issued by the PGA Tour detailing the changes on the Blue Monster:

-Rebuilt and reshaped all the greens.

-Rebuilt and repositioned all the bunkers.

-Rebuilt all the tees.

-Rebuilt all the fairways.

There was nothing about the helipad, positioned between the ninth and 10th holes.

Woods, who withdrew from the final round of the Honda Classic on Sunday with a lower back injury that produced spasms, arrived in time to cut the ceremonial ribbon on the Tiger Woods Villa (where Rory McIlroy is staying) and hold a 20-minute news conference to say that treatment has improved his back and that he was looking long term at ways to keep it from happening again.

Then, he took wedges and a putter and walked 18 holes to see the place for the first time.

It was the second time in 10 tournaments that Woods experience back pain during a round. It was the fourth time in five years that he withdrew in the middle of a round because of injury. For a guy with four surgeries on his left knee, the focus has shifted to his lower back.

“I think we have to take a more global look at it, absolutely, because it comes and goes,” Woods said. “We’ve got to make sure that we do preventative things to make sure that it doesn’t happen and adjust certain things, whether it’s swing, lifting, whatever it may be. You have to make certain adjustments. We’ve done that throughout my entire career, and this is no different.”

He turned 38 last year, though health concerns are nothing new. He had the first of his four knee surgeries while at Stanford. He said he first experienced back pain in college.

“I’ve had a knee injury, wrist injury, elbows, you name it. Now I’ve had back, neck. It’s the nature of repetitive sport,” Woods said. “We do the same motion. Some guys do it a thousand times a day, but it’s the same exact motion. So you have repetitive injuries and most of my injuries are that. So that’s the nature of why we lift, why we work out - to prevent a lot of these things and keep us healthy and keep us out here.

“As we get older - and I’ve learned it as I’ve aged - I don’t quite heal as fast I used to.”

The real concern is his back, however.

Woods said even with shredded ligaments and two stress fractures, he was able to win the 2008 U.S. Open at Torrey Pines because the pain didn’t arrive until after he had launched his shot. He said at the Honda Classic, his movement became so restricted that he couldn’t rotate his body. The pain occurred as he was starting his swing and affected how he struck the ball.

“A bad back is something that is no joke,” he said. “With the back, it’s a totally different deal. There are certain movements you just can’t do. That’s one of the things I’ve started to learn about this type of injury.”

He plays the opening two rounds in the traditional 1-2-3 grouping based on the world ranking. The question is whether it stays in that order by the end of the week. Masters champion Adam Scott is No. 2 (Henrik Stenson is No. 3), and he would have a mathematical chance of going to No. 1 if he were to win.

“I think it is absolutely a good pairing with the No. 1 up for grabs,” Scott said. “I don’t know how Tiger feels about it, but it’s obviously a position he’s pretty comfortable with for a long time throughout his career. And I can assure you from knowing him just a little bit, it’s a position he probably wouldn’t want to give up.

“So I don’t know that we’re going to be trying to play each other head-to-head because we know this field is a lot bigger than the two of us.”